Allergic Rhinitis

• Allergic rhinitis is a common disease affecting 10-30% of the population
• Highest prevalence is found with school aged children
• 80% of patients with allergic rhinitis are diagnosed before age 20
• Up to 30% of adults and 40% of children across industrialized nations are affected
• There are no prevalence variations based on gender or sex after age 20

Etiology

• Allergic rhinitis is a multifactorial condition that develops through genetic and environmental interactions

Allergic Rhinitis

• An exaggerated immune response pertaining to nose inflammation
• Allergy is an exaggerated immune response to a foreign antigen, regardless of mechanism
• Atopy is an exaggerated IgE-mediated immune response, all atopic disorders are type I hypersensitivity disorders
• Foreign antigens for allergic rhinitis are aeroallergens

Atopic Disorders

• Commonly affects the nose, eyes, skin and lungs
• Disorders include conjunctivitis, atopic dermatitis, asthma, and allergic reactions to venomous stings
• Allergic rhinitis and asthma frequently coexist
• It is unclear whether rhinitis and asthma both result from the same allergic process, or if discrete asthma trigger rhinitis

Risk Factors

• Personal or family history of atopy can increase a patient's likelihood of developing allergic rhinitis
• Risk with 1 parent increases the risk to 30%, while 2 parents increases the risk to 50%
• Exposure to specific allergens in utero or early childhood has been shown to increase the development of allergic rhinitis
• Geographic location (or western lifestyle) and pollution exposure
• Being less than 20 years of age can increase the likelihood of allergic rhinitis

Pathophysiology

• Type I Hypersensitivity is happening specifically in the nasal mucosa

Phase 1: Sensitization

• The onset occurs at first contact with the allergen
• Immunoglobulin E (IgE) is produced and binds to receptors on the surface of mast cells and basophils

Phase 2: Immediate Reaction

• Symptoms develop within minutes and lasts between 30-90 minutes
• With re-exposure, the allergen binds to allergen-specific IgE and mast cells release preformed mediators and newly generated mediators including:
  • Histamine
  • Tumor necrosis factor-alpha [TNF-alpha]
  • Leukotrienes [LTC4, LTD4, LTE4]
  • Prostaglandin D2
  • Kinins

Phase 3: Late Reaction

• The onset is 4-8 hours post-exposure
• Characterized by migration of inflammatory cells:
  • Eosinophils
  • Monocytes
  • Macrophages
  • Basophils

Clinical Presentation

• Extra creases at the lower eyelids (due to edema)
• Discolored infraorbital areas due to venous stasis (resulting from nasal swelling)
  • Dark circles or bruising under the eye
• Conjunctival redness fading toward the edges of the eye
• Allergic shiner
• Allergic salute (at the junction of the bulbous portion of the nose)
• Other symptoms include:
  • Postnasal drip
  • Loss of smell or taste
  • Chronic cough
  • Throat clearing
  • Malaise
  • Fatigue
  • Ear fullness
  • Popping
  • Forehead Ppressure
  • Cheek Pressure

Clinical Diagnosis

• Diagnosed based on patient’s symptoms, health history and a physical exam
• Typical history will include:
  • Nasal and or ocular symptoms
  • Seasonal or perennial symptom pattern
  • Identification of precipitating factors
  • Identification of coexisting atopic conditions
• Skin-prick testing provides evidence of an allergic basis for symptoms, to confirm/exclude suspected causes of symptoms; can assess the sensitivity to a specific allergen to determine avoidance measures and/or allergen immunotherapy
• In-vitro assays are used for specific IgE determination, these are more expensive and less sensitive
• Used for patients with severe eczema, significant dermatographia, or those unwilling to stop their antihistamines

Differential Diagnosis

• Other considerations can include:
  • Hormones
  • Pregnancy, menstruation or hypothyroidism
  • Upper Respiratory Tract Infection (URTI)
  • Viral, Bacterial, or fungal infections
  • Climate Change
  • Cold aid
  • Strong Smells
  • Emotions (eg Stress)
  • Exercise
  • Anatomic Abnormalities
  • Food
  • Pollutants
  • Tobacco
  • Drugs

Considerations for Drug Induced Rhinitis

• Agents include:
  • ACE inhibitors
  • ASA and other NSAIDs
  • Calcium channel blockers
  • Cocaine
  • Diuretics
  • Gabapentin
  • Hydralazine
  • Oral contraceptives
  • Phosphodiesterase-5 inhibitors
  • Psychotropics
  • Sympatholytics
  • Topical decongestants (prolonged use)

Is it a cold/Flu or Allergies?

• Both allergic rhinitis and cold/flu share symptoms like:
  • Rhinorrea
  • Congestion
  • PND
  • Cough
  • Headache
  • Sneezing
• Allergic rhinitis is specific since it includes:
  • Seasonal pattern
  • Identifiable aeroallergen triggers
  • Nasal, throat or ocular itching
• Common flu traits include:
  • Seasonality in fall and winter
  • Fever
  • Myalgias and Malaise
  • High transmissibility

Classification of Allergic Rhinitis

• ARIA Classification:
  • A way to diagnosis and classify
  • Intermittent- <4 days a week OR <4 consecutive weeks/year
  • Persistent- ≥4 days a week AND ≥4 consecutive weeks/yearly Symptom Severity:
  • Do symptoms effect; daily activity, sleep, work/school or hobbies/leisure

Referral Criteria

• Any fever, headache, earache or sore throat must be referred
• Discoloured nasal mucus
• Postnasal drip with thick mucus
• Taking medicine associated with causing rhinitis
• Past illicit nasal drug use
• Patient is pregnant
• Patient presents with unilateral nasal obstruction
• Patient < 2 years of age
• Any symptoms indicating hypothyroidism
• Symptoms only occur with changes in temperature, humidity or barometric pressure

Key steps in assessing a patient

• Ask the patient to describe all presenting symptoms
• Eliminate all red flags
• Rule in diagnosis based on a summary of all data
• Classify to what degree allergic rhinitis is present

Goals of Therapy

• Alleviate any current signs or symptoms
• Improve patient lifestyle
• Minimize daily interference
• Prevent any adverse side effects
• Prevent reoccurrence of symptoms
• Decrease medication costs
• Consider resonable parameters with timeframe

Approach to Management

• Allergen or irritant avoidance is key step
• If effective no therapy may be needed
• If impractical; mild or infrequent symptoms can be managed with; intranasal saline spray
• Severe symptoms can be managed with regular use of intranasalcorticosteroid

Non-Pharmacologic Therapy

• Limiting time outdoors increases during high pollen times
• Removing any excess moisture reduces the risk of fungal exposures
• Combination of humidity control, dust mite covers as bedding helps treat mites
• Avoiding pets helps lower dander levels
• Removing things like tobacco smoke lowers risk of rhinitis

Pharmacologic Therapy

• Agents includes:
  • Intranasal Saline
  • Intranasal / Oral decongestants
  • Intranasal / Oral antihistamines
  • Intranasal Corticosteroids
  • Intranasal Anticholinergic
  • Oral Leukotriene Receptor Antagonists
  • Ophthalmic Agents
  • Immunotherapy

Intranasal Saline

• In the form of sprays, drops, or irrigation
• Strength between 0.9% and 3%
• Direct cleansing helps remove inflammatory mediators
• Can be used alone or adjunctive
• Most common ADR is; minor discomfort, stinging, & ear fullness
• Distilled or boiled water for irrigation is mandatory
• Patients with trauma or neurological problems should not irrigate or need special care

Decongestants

• Provides temporary symptom releif
• Intended for short term use only
• Alpha-adrengeric agonists cause vasoconstriction
• Relieves nasal obstruction

Antihistamines

• Block H1 receptor
• Inhibiting effects of histamine

Intranasal Corticosteroids

• Effective with rhinorrhea, congestion & sneezing

Oral Leukotriene Receptor Antagonist

• Moderately effective for rhinorrhea, nasal itch and sneezing

Anticholinergics

• When applied it reduces secretions

Other Options: Immunotherapy

• This is otherwise known as allergy shots or desensitization
• Available for dust mites, grass pollen, and ragweed pollen
• This treatment is only reserved for moderate or severe rhinitis patients that have shown little to no progress with tradition treatments
• Small amount of allergen is administered sublingually or subcutaneously to slowly build tolerance
• Precautions: avoid if; severe ashtma or preganant patients

Pregnancy Considerations

• Note that Rhinitis is common in Pregnancy
• Antihistamines: All cross the placenta. Preferred treatment is 1st gen chlorpheniramine or diphenhydramine
• Intranasal Corticosteroids: Safe, beclomethasone, budesonide, and fluticasone are preferred.
• Intranasal Anticholinergic: Crosses the placenta, can harm the fetus. Use if after other first line agents
• Oral decongestants should be avoided, particularly within the first trimester